The abolition of the deputy director general post at the BBC, and the imminent departure of the man who occupies it, Mark Byford, brings an urgent issue to the fore – succession planning.

It is widely assumed that director general Mark Thompson is planning to exit about 2012 once the London Olympics have taken place, ideally after he has also negotiated the next licence fee settlement.

Who might replace him? Byford was not blessed with the public poise and surefootedness required to do the very top BBC job. Another problem is that he is a BBC lifer, with no outside experience.

As deputy to Thompson he performed a useful role as a loyal, supportive ally, rather than a competitor for the top job.

By heading the BBC's journalism, the part of the corporation's output which inevitably attracts controversy, Byford was Thompson's shield, but that is a luxury the BBC can no longer afford.

"He could spot the flying omelettes coming over the horizon," said Ron Neil, the former managing director of BBC news and BBC television.

But Byford, and other immovables on the executive board, have also acted as a block for the ambitious.

So who is qualified to be in the frame as the next director general of the BBC?

It would seem that recruiting an executive who has risen through news and current affairs, the path to the top which Thompson trod, is now out of favour.

I consulted another expert, who said: "I could have counted four or five people a few years ago. Now, as I look across the whole television industry, I can't name anyone at all. Who is there of calibre, and who would want the job?"

Caroline Thomson, the chief operating officer, on the board for the past decade, is seen as very able, and she has worked at Channel 4, but is associated with several of the current BBC regime's public failures.

Peter Horrocks, the director of Global News, is another executive with aspirations, but it could be that the BBC will look outside the organisation for its next leader.

John Birt, in his final years, encouraged a group of ambitious BBC executives to aim for the top job – but it went to Greg Dyke instead.

The next chairman of the BBC Trust will be making the final decision, and he has not yet been chosen.

Sir Terry Leahy, the outgoing chief executive of Tesco, is in the frame, and if it not him it is likely to be someone with considerable business expertise.

There are also whispers that the powerful trio of businessmen who serve as non-executives on the BBC executive board, have taken a measure of top BBC management talent – and believe that high-level management skills, outside experience, and proven ability at managing a multibillion-pound organisation are prerequisites for the top job.

The problem with that approach is it risks devaluing the key skill of acting as the BBC's editor-in-chief – which requires an ability to deal with those "flying omelettes".

Mark Byford is now keen to build a new career elsewhere, with charity work to the fore. He may find a role model in Tony Hall, a former head of BBC news and current affairs. He missed out on the director general job when Dyke was appointed, but is now the successful chief executive of the Royal Opera House.

One of Byford's first new activities post-BBC will be assisting the RNLI with fundraising and communications. Is it time for other senior executives at the BBC to send for the lifeboats?